Chen and co-workers suggested that as many as 30% of patients with type I GSD would develop chronic kidney disease by age 20 years. We have evaluated 14 patients, age 6 months to 34 years and found no evidence of renal disease, although several showed increased renal blood flow and glomerular filtration. The likelihood of renal disease appears related to poor control of diet. Patients are being evaluated at 2-3 year intervals for possible progression to renal disease and evaluation of GFR.